[matts37chev]

Originally Posted by sqzbox

Like mine? 4:09's in the front and 4:10's in the rear. I only have 31" M/T's
but in low range, 3rd gear is like first in high range.The secret to full pulls is wheel spin like seeing 70 mph on the speedo all the way through the pit.

thats right, 4:09's and 4:11's would be even better.
you might try just putting 4:56's in the rear and see what that does
the other way to do this is put a little taller tire in front.
keep the 35's in the rear but then put some 37's in the front.
or are you in a 35" and smaller class?
what is the actual tire size you are running?

[inquiring_mind2]

I am running eagle rods in it.

[inquiring_mind2]

thats right, 4:09's and 4:11's would be even better.
you might try just putting 4:56's in the rear and see what that does
the other way to do this is put a little taller tire in front.
keep the 35's in the rear but then put some 37's in the front.
or are you in a 35" and smaller class?
what is the actual tire size you are running?



I thought about putting 513 in the front and 456 in the rear??? or is it the other way around??513 in rear and 456 in front?? I am in the 35 and under tire class. That is how we run them around here. so I have to keep the 35 in tires in mind when I am trying to decide on what to do

[inquiring_mind2]

I also want the wheel speed that is why I thought about a taller gear so that way I could go from second to drive and then back down if I needed to

[matts37chev]

Originally Posted by inquiring_mind2

I thought about putting 513 in the front and 456 in the rear??? or is it the other way around??513 in rear and 456 in front?? I am in the 35 and under tire class. That is how we run them around here. so I have to keep the 35 in tires in mind when I am trying to decide on what to do

yes, it is the other way around.
bigger number is lower (or shorter) gears
smaller number is higher (or taller ) gears

5:13 in the rear and 4:56 in the front is a big spread
might be better with
4:88 in the rear and 4:56 in the front, or
5:13 in the rear and 4:88 in the front

i originally suggested just putting the 4:56 in the rear because it would be cheaper, only doing one end
however thats not much of a jump

[inquiring_mind2]

yes, it is the other way around.
bigger number is lower (or shorter) gears
smaller number is higher (or taller ) gears

5:13 in the rear and 4:56 in the front is a big spread
might be better with
4:88 in the rear and 4:56 in the front, or
5:13 in the rear and 4:88 in the front


Ok great now my next question is if I would go with the 513 in the rear and 488 in the front will I be about 6800 RPM'S?? I am running the turbo 350 and the dana 300 transfer case. And I would be running the low side and I am wanting to be in drive for the wheel speed..I am not real familiar with how all of this stuff works together. Obviously that is why I came and asked the best people around

[matts37chev]

i cant find the calculator im looking for
but if you call these guys they can fix you up
http://www.ringpinion.com/Default.aspx

the other thing that makes that tricky is two different gear ratio's you kind of got to split the difference in calculating rpm's

[sqzbox]

From the look of your jeep in your avatar you've done this before. So, how are you doing up to this point? 100 ft. 150 ft. The first two times I ran the bog I only made it 102 ft. before killing the engine by plugging up the air filter because I was too stupid to realize an open element is not the way to go.
Truck was doing a good job for a pure stocker but I need to switch to a closed system with remote air intake to do any good beyond that. Maybe next season. The guy's that went the farthest or all the way through had their wheels spinning about 100 mph. with no drop in RPM till the end of the track or buried themselves in the goo about 2/3rd's of the way.

[inquiring_mind2]

I Am doing ok the pit we use is 200 ft. I can go about half way and I bogg down. No one in my class usually clears the pit. But I am wanting to clear the pit so I am trying to figure out the gearing so I can make it out. You are right about the wheel speed. so that is why I am here to see if I can get mine to that level

[inquiring_mind2]

thanks MAtts37chev I will give them a call and see what they have to say

[big gear head]

http://www.ringpinion.com/Calc_RPM.aspx
If you play with this you can probably figure out what you need. You will need to know your gear ratios in the transmission and transfer case to make it work right.

[matts37chev]

i used to have a tire size, gear ratio,rpm chart, but i cant find it

[inquiring_mind2]

ok thanks Big Gear Head

[sqzbox]

Originally Posted by matts37chev

i used to have a tire size, gear ratio,rpm chart, but i cant find it

And your only 41? You ain't seen nothing yet!

[inquiring_mind2]

sqz what part of Indiana are you from